Synthesis And Bioactivity Of Novel Phenyl 1,2,4-Oxadiazole-Containing,Pyridyl-piperazine Derivatives

Oxadiazole structure has been widely studied in the field of insecticide and sterilization,especially in recent years,the structure of 1,2,4-oxadiazole has been extensively decorated and modified,and special heterocyclic compounds have been synthesized by intramolecular ring formation reaction and 3,5 substituent structure modification.It is derived from many novel structural compounds due to the different substituents.Piperazine is widely used in the field of medicine.It can still play a key role in the field of pesticides by virtue of its unique bridge chain and activity.The high insecticidal and acaricidal activity of trifluoromethylpyridine structures has been reported frequently.So monosubstituted intermediates synthesized by piperazine and trifluoromethylpyridine will also have important high activity researchful significance.In this paper,5-bromo-2-ethoxybenzylammonium and 1-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)piperazine(IIIc1)were used to synthesize five(5-bromo-2-ethoxyphenyl)-1,2,4-oxadiazole target compounds and thirty-one fluorine-containing pyridyl piperazine target compounds by intermediate derivatisation methods and key intermediate IIIc1 was optimized for the process to find the optimum process conditions.All compounds were confirmed by ~1H NMR and elemental analysis after purification.Screening of target compound structures using biological activity experiments,and the structure-activity relationship between structures was discussed to find high-activity groups,which provided a reference for the research of new pesticides.The test of oxadiazole target compounds found that the insecticidal activity(Plutella xylostella,Spodoptera exigua)of compounds II6a,II6e were more than 70%;the two highly bacteriostatic active compounds II6b,II6e were more than 80%for Gibberella zeae and more than 70%for Helminthosporium maydis,of which compound II6e had both insecticidal and bactericidal activity.The test of fluorine-containing pyridyl piperazine target compounds showed that plutella xylostella activity of compounds IIId11,IIId18and IIId28 were more than 95%,and the Spodoptera exigua activities were more than83%;the activity of compounds IIId4,IIId14 and IIId28 were more than 94%against eggs of T.cinnabarinus,and acaricidal activity were more than 98%against adults,and the compound IIId28 had both insecticidal and acaricidal activity.